Troy Firearms Rail Covers are engineered to survive the most extreme conditions. Constructed from durable, heat & chemical-resistant synthetic polymer resin, The Troy Firearms Rail Cover quickly and easily slides onto a 1913 Picatinny Rail and locks into place with a built-in retaining clip. No tools required. The Troy 3 in rail covers allow the users greater placement options when using scopes, mounts and other mounted accessories when space is limited.